"He isn't God," she said, "he's actually being very human; trying to get money invested in his technology and avoid regulation that would restrict its use."

But Dr Venter said that he was "driving the discussions" about the regulations governing this relatively new scientific field and about the ethical implications of the work.

He said: "In 2003, when we made the first synthetic virus, it underwent an extensive ethical review that went all the way up to the level of the White House.

"And there have been extensive reviews including from the National Academy of Sciences, which has done a comprehensive report on this new field.

"We think these are important issues and we urge continued discussion that we want to take part in."

Ethical discussions

Dr Gos Micklem, a geneticist from the University of Cambridge, said that the advance was "undoubtedly a landmark" study.

But, he said, "there is already a wealth of simple, cheap, powerful and mature techniques for genetically engineering a range of organisms. Therefore, for the time being, this approach is unlikely to supplant existing methods for genetic engineering".

The ethical discussions surrounding the creation of synthetic or artificial life are set to continue.

Professor Julian Savulescu, from the Oxford Uehiro Centre for Practical Ethics at the University of Oxford, said the potential of this science was "in the far future, but real and significant".

"But the risks are also unparalleled," he continued. "We need new standards of safety evaluation for this kind of radical research and protections from military or terrorist misuse and abuse.

"These could be used in the future to make the most powerful bioweapons imaginable. The challenge is to eat the fruit without the worm."

The advance did not pose a danger in the form of bio-terrorism, Dr Venter said.

"That was reviewed extensively in the US in a report from Massachusetts Institute of Technology (MIT) and a Washington defence think tank, indicating that there were very small new dangers from this.

"Most people are in agreement that there is a slight increase in the potential for harm. But there's an exponential increase in the potential benefit to society," he told BBC's Newsnight.

"The flu vaccine you'll get next year could be developed by these processes," he added.